SoftBank bought the seven-year bond from Sprint at the time
of its initial bid in October, an investment it wasn’t initially
permitted to sell without Overland Park, Kansas-based Sprint’s
consent, according to regulatory filings. This week, the two
amended the terms on the debt so the suitor has the right to
sell the bond back if it loses out to Dish.

Before today, Sprint had risen by almost one-third since
agreeing to a $20.1 billion bid from SoftBank, which was later
sweetened. That would leave Dish having to pay $1.2 billion more
than SoftBank paid, the filings show, based on the 30-day
trading average of Sprint’s stock. That cost is the latest in a
string of obstacles for Dish Chairman Charles Ergen, who has
spent the past two months jostling with SoftBank for control of
the third-biggest U.S. wireless carrier.

In October, Sprint issued $3.1 billion of convertible debt
to SoftBank, which intended to swap the debt for about 590.5
million shares. The difference between the initial conversion
price of $5.25 and the current trailing price of about $7.30
represents the potential extra cost Dish would face to
repurchase the securities.

Dish, based in Englewood, Colorado, made an unsolicited bid
to acquire Sprint in April, which was valued at about $7 a
share. The bid includes $4.76 cash and 0.05953 Dish share for
each Sprint share. Dish faces a June 18 deadline to submit a new
bid after SoftBank increased its own offer this week to about
$7.65 a share.

The amendment to the bond-purchase agreement coincides with
Sprint’s decision to implement a shareholder rights plan, or
poison pill, to prevent Dish from turning hostile and
accumulating the majority of Sprint shares. Sprint and Tokyo-based SoftBank also agreed to boost the breakup fee on the deal
to $800 million from $600 million.